Method of operating blast-furnaces.



Patented Apr. 29, [902.

J. KENNEDY.

METHGD 0F OPERATING BLAST FURNACES.

(Application filed May 8, 1901.)

2 Sheets-Shut I.

(No Model.)

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No. 698,840. Patented Apr. 29, I902.

, J. KENNEDY.

METHOD OF OPERATING BLAST FURNACES.

(Application filed m a, 1901.) I

(No Model.) 2 Sheets-Sheet 2.

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UNITED STATES PATENT OFFICE.

JULIAN KENNEDY, OF PITTSBURG, PENNSYLVANIA.

METHOD OF OPERATING BLAST-FURNACES.

sienotnxoarron forming m of Letters Patent No. 698,840, dated April 29, 1902.

Application filed May 3, 1901. Serial No. 58.609. (No model.)

To all whom it Hwy concern: 7

Be it known that I, JULIAN KENNEDY, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Method of Operating Blast-Furnaces, of which the following is a full, clear,

- and exact description, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a side elevation, partly in section, of a blast-furnace system arranged for carrying out my invention. Fig. 2is an enlarged side elevation of the hand-valve mechanism, and Figs. 3 and 4 are respectivelya top'plan and sideQelevation showingon a larger scale the automatic valve mechanism of Fig. 1.

My invention relates to the operating of blast-furnaces, and is designed to prevent the throwing out of the coke and other parts of the charge when a slip occurs and a part of the charge drops in the furnace. When the charge in a furnace arches over and hangs,

it drops after a certain time and causes a sudden and .large upward rush of the confined gases, and consequently a great increase in the pressure at the top of the furnace, which throws out quantities of coke, &c., and to allow as freeescape as possible of the'suddenlyreleased gases explosion-doors have been used which are opened by the excess pressure, the coke being thrownout through these openings. My invention is designed to largely prevent this heaving out of coke from the furnace by choking the outlet of the imprisoned gases, and thus holding them back and preventing this throwing out ofthecharge when a slip occurs,-and-I have found that by throttling the gas offtake-pipe before the slip occurs the gases are momentarily held back in the furnace and the large excess allowed to I escape gradually, thus preventing the throwa sudden outward Figs. 1, 3, and 4, 2 represents a blast-furnace having a do'wncomer System23, which leads the gases from the top of the furnace tothe dust=catcher 4. From this dust-catcher the gas-main 5 leads to the boiler-furnaces,

toothed segment 22.

hot-blast stoves, or other points where the gases are burned. In this pipe 5, and preferably near the dust-catcher, 1 place a butterfly-valve 6, whose shaft"? extends through one side of the pipe and is provided with a bellcrank lever. The one arm 8 of this bell-crank is provided with a counterweight 9, while the other arm 10 is normally held in place by a sliding catch 11, movable through guide 12 and secured to the piston-rod of a single-acting cylinder 13. 'lhecatch is normallyforced forward into the position shown in Figs. 1 and 4 by a strong spiral spring 14., the pressure ofwhich may be regulated by screw 15, having an inner cap engaging the end of the spring. This cylinder may be supported from the side of the gas-main, as shown, and to the opposite side of the piston leads'a pipe 16, which extends from the dust-catcher and is open to the pressure therein. With this device the spring is regulated 'to normally hold the valve in the position to give the ordinary normal pressure, and when excess pressure is suddenly accumulated at the top of the furnace, as in the case of a slip, the piston will be immediately jforced back, releasing the catch and allowing the'weight to partly close the valve. The amount of this closing may be regulated by adjustable stoppins 17 in a segment 18 and arranged to contact with the counterweighted lever-arm.

After-this automatic closing of the valve is effected, thus choking back the gases in the furnace-top, the pressure willgradually reduce by escaping through the pipe around the valv'e,'and the spring will force the piston back-to its normal position. The catch is adjusted by-hand, and'the parts are then left in this position. Aliquid pressure-gage 19 is preferably placed between the valve and the dust-catcher to enable the pressure to be ascertained at any time.

Instead of operating the valve automatically I may actuate the valve by hand, as the operator can judge from the irregular operating of the furnace when to'throttle the outlet prior to the slip. Thus in Fig. 2 I show the valve as provided with a'hand-lever 20, having a spring-pressed catch 21, engaging a The Valve may thus be IOC locked in any adjusted position, and by withdrawing the catch the valve may be turned and readjusted.

In regulating the furnace by this system the butterfly-valve 6 is normally opened to the extent necessary to give the low pressure usually maintained in the pipe system, two ounces being an ordinary pressure. When, however, the furnace begins to work irregularly and to hang, as shown, by sounding the top of the furnace charge to ascertain its rate of descent or by observing the action of the engine, which will slow down, then in such case the operator partially closes the butterfly-valve, thus throttling down the gas-outlet until the pressure between this valve and the furnace is considerably raised-say to eight ounces, for example. This pressure is not normally carried, because of leakage of gas around the top of the furnace, but does no harm when raised for short periods. When the slipoccurs and the mass of material in the furnace drops down, there is a sudden upward rush of gases under pressure to the outlet, which would ordinarily carry out a considerable quantity of coke; but the gasoutlet system having been throttled down the gas is choked back and not allowed to escape freely, and hence while the pressure will probably reach several pounds at the top of the furnace, yet on account of the slow escape of this pressure the materials are not heaved out of the furnace. With either form of the system I also preferably make the top of the furnace stronger than usual, the top structure being firmly held down to prevent its being heaved up by the excess pressure. After the pressure is again lowered the throttlevalve is turned back to its normal position, the pressure is reduced, and the operation goes on as before.

The advantages of my invention flow from the holding back of the suddenly-generated excess gas-pressure, thus preventing its sudden release and consequent throwing out of material. This principle of constricting the gas-outlet to regulate the action of the furnace, especially just before a slip is liable to occur, I consider broadly novel.

Many changes may be made in the apparatus employed and in the position of the valve or other throttling mechanism without departing from my invention as defined in the claims. a

I claim 1. The method of preventing the discharge of coke after a slip, in a blast-furnace, consisting in reducing the area of the gas-olftake when the charge in the furnace is hanging; substantially as described.

2. The method ofoperatingablast-furnace, consisting in reducing the area of the gasoutlet when the pressure increases in the furnace; substantially as described.

3. The method oficontrolling a blast-furnace and preventing accidental discharges, consisting in throttling down the outlet and choking back the gas-pressure when a slip occurs; substantially as described.

In testimony whereof I have hereunto set my hand.

JULIAN KENNEDY.

Witnessesi F. MoOLAIN,

GEO. B. BLEMING. 

